Process vessels lined with refractory concrete, bricks and other ceramic materials are used in a number of applications including in the cement, petroleum, petro-chemicals, mineral processing, alumina and other industries. From time to time the linings break down and need to be replaced or repaired. Failure in the lining of a process vessel includes de-bonding of the refractory layers, failure of anchor supports, delamination, voiding, cracking or honeycombing in the refractory layers, and the like.
In order to maintain process vessels that are lined with refractory materials, it is generally necessary for the process vessels to be taken offline and the refractory lining to be inspected. Taking a process vessel offline for the inspection of refractory linings when the refractory lining is in good order is unnecessary and may result in loss of productivity. Certain process vessels may take many hours, or even days, to cool sufficiently or to be in a condition for inspection. The inspection of the refractory lining is also a potentially hazardous operation. Operators enter a process vessel in order to inspect and determine the condition of the lining. Incidents have occurred where linings have fallen from a process vessel while an operator has been inside the vessel.
In addition to visual inspection from inside the process vessel, a variety of destructive tests may be used to determine the integrity of the refractory lining. For example, core drilling has been used in order to assess the integrity of the refractory lining. Destructive testing is not generally desirable as the testing itself can compromise the integrity of the lining.